The invention relates to the subject matter of the claims.
It is known that 3.beta.-acetoxy-5-hydroxy-5.beta.,17.alpha.-pregn-6-ene-21,17-carbolactone can be prepared from 3.beta.-acetoxy-5,6.beta.-epoxy-5.beta.-pregnane-21,17-carbolactone via the intermediate stage of 3.beta.-acetoxy-5-hydroxy-6.alpha.-phenylseleno-5.beta.-pregnane-17,21-car bolactone [Helv. Chim. Acta 62: 2276(1976)].
This process has the disadvantage, however, that highly toxic organoselenium compounds, such as, for example, diphenyldiselenide, are required for the synthesis, the handling of these compounds presenting difficulties on an industrial scale; disposal of the wastes of these compounds can only be made in special dumps, and furthermore these compounds are not likely to be available as a raw material in abundant amounts.